Many higher-end cars and trucks now come equipped with keyless entry systems. These typically take the form of a pocket-sized fob with several pushbuttons that unlock doors and perform other functions through encoded RF signals transmitted to a vehicle-installed receiver. Depending upon the sophistication of the system, keys may be provided to activate and deactivate alarms, turn lights on or off, and even start the car on cold days. Though convenient, keyless entry systems of the type just described may cost several hundred dollars, even if factory installed. As the costs of electronic hardware has decreased, the use of these systems have proliferated even with less expensive vehicles.
Certain types of vehicles, luxury cars in particular, also come equipped with door-mounted keyless entry systems. These typically take the form of a keypad strip positioned close to the door handle, enabling an authorized user of the vehicle to punch in a numeric code and gain entry to the vehicle. These keypad strips are generally low in profile for easy maintenance. There are also vehicles equipped with both wireless and door-mounted keyless entry systems, but they are generally unrelated in terms of electronic protocol. That is, the wireless systems transmit RF codes, whereas the door-mounted systems are hard-wired and do not require sophisticated encoding.
The present invention addresses the desire to combine wireless and vehicle-mounted keyless-entry modalities in a cost-effective system configuration. Although there are many patents and other references related to the problem of keyless-entry, none address the problem solved by the instant invention. U.S. Pat. No. 5,467,080 to Stoll et al., for example, discloses a hardwired, keypad-actuated, keyless entry system where the keypad is integrated into the body of the car. This patent resides in the use of a capacitive, touch sensitive keypad, and does not discuss the use of a wireless transmitter.
U.S. Pat. No. 5,252,960 to Duhame discloses a keypad entry transmitter for use with a garage door opener. A wireless transmitter including a keypad is mounted outside of the garage such that when the proper code is entered into the keypad, the transmitter delivers a garage door opening signal to a receiver mounted inside of the garage. This patent fails to disclose a vehicle mounted keypad in general, or the use of keys operable through glass, in particular.
U.S. Pat. No. 5,077,831 to Weber discloses a wireless transmitter which requires the code to be input before the transmitter becomes active. This patent fails to disclose a vehicle mounted transmitter or any details of the code input portion.